Manufacture of varnishes.



' E. H. STRANGE.

MANUFACTURE OF VARNISHBS. APPLICATION FILED FEB. 26, 1910.

I Patented Dec. 12; 1911.

' TTNITED STATES PATENT OFFIiCE."

EDWARD 'mulronn srnnnen, or smrnn INN, Lennon; ENGLAND, nssreivon oroNE HALF r EDMUND nrsomnnn BURRELL, or MIDLwALn-Lomom ENGLAND.

Manuracrunn or, vannrsnns.

- To all whom it may Be it known that I, Eowniio HALroRn S'rnANen'M. fSc.,'a subject of-the Kin of Great- Britain and Ireland, of-Z Staple rm, in the countyof London, England, have invented new and useful-Improvements in the,

Manufacture of Varnishes, of which the :tol-

- lowing is a specification.

This invention relates or resin, commonly knownas copal, is heat -ed with a' solvent under pressure in a drgester, without any linseed, or l1ke,'o1l be-y ingpresent during digestion. Such a proc-.

I .copalthan is necessary to be present in the which the process may be carri finished varnish, and owing to the great pressure generated in this digester at thetemperature required for efi'ecting solution "(usually a pressure of between 450 and 600 lbs. to the square inch), a'digester of a very cumbrous and expensive character has to be provided to give the requisite strength to withstand the pressure, especially as, at the high temperature employed, steel is liable to have its normal strength lessened, and the process is tlierefore,.to a corresponding extent. dangerous and expensive.

Objects of'this invention are to make the process quite safe and also cheaper and. the plantvery much lesscumbrous and expensive. V

An apparatus is diagrammatically illustrated. in the accompanying drawing 1n out.

According to the present invention, instead of using a completely closed digeste'r A, I employ a digester which is provided with a distilling head, or pipe, or the equivalent- B Whichiskept open so as to give,

during the whole of the dissolving process, communication between the digester and an outlet, preferablyto a condenser C, the outlet valve D being regulated so that the pressurein the digesterdoesnot exceed two hundred and fifty lbs. to the square inch, or-"thereabout,.thi s pressure being a-convenient and safe one to work at. In working' under these conditions, with, say, fourparts-by weight of copa l and. one part by. weightiof solvent, agcomiiletejsolutlon of the;

to the process of making varnish,*in which process hard gum,

Specification of Letters Patent. Patented Dec; 12, 1911. Application u e February 26, 1910. Serial No. 546,050,

copal can be obtained before the whole of the solvent has been'volatilized. I

Inthe specificationsof the aforesaid rior patents, it is stated that sin-excess of V0 atile solvent is employed, but, according to the processof the-presentinvention, much less solvent is required than will be required in the varnish manufactured; for instance, the

l n "can be efiected with as little as 1 about one-tenth (if-the weight of solvent required in the finished varnish. This enables solventstobe employed, for effecting the solution'of thecopah which it is desirable shall not be present, or not present to any objectionableeigtent, in finished varnish of good quality for instance,'volat-ile fractions of the distillation of shale"oil, or of petroleum, known as turpentine substitute,

can be employed for efiec'tin the solution of the copal in the 'digester, t i'ese being very 'efiicient and much cheaper than American turpentine, and the do not decompose, or give rise to objectionable products by pro fected by the heatof the dissolving process,.

but, if desired, for commoner varn shes, volatile solvents, such as fractions of the distillation of petroleum, or of shale'oil, can be used instead of turpentine to make the finished varnish of the requisite consistency. A further-advantage of this invention is that when American turpentine is used inthe digester as the solvent in accordance with the process of the aforesaid specifications, objectionable products are liable to be formed and the odor of the American turpentine is affected, and although it may not affect the practical'utility of, the varnish, the absence ofthis odor of American turpentine is prejudicial to the sale of the finished varnish and, as in the process according to this invention, the turpentine is added subsequently to dissolving and at a lower temperature, no objectionable products are formed therefrom and the desirable odor fot the turpentine is retained.

longed heating and, by .the time the solu' If the varnish is to be an oil varnish,.in-

stead of a spirit varnish, linseed oil is added after the treatment in the digester and at a temperature. of, say, about 100 centi: grade. If it be required to filter, or allow impurities to settle, this can be effected after the product from the digester has been thinned suhicien'tlyfor this purpose and, in the case of oil varnishes,-before the oil is addedt a Driers may be addedto the varnishes if desired.

W'hat I claim is 1. The process of manufacturing .varnish which comprises the step of dissolving copal by heating the latter under pressure but'not materially in excess of 250 pounds to the square inch, in the presence of'a quantity 0? a volatile solvent less than required in the finished product.

2. The process of manufacturing varnish which comprises the step of dissolving copal by heating the latter under pressure but notmaterially in'excess of 250 pounds to the square inch, in the presence of a quantity of a volatile solvent less than required in the finished product and simultaneously dis- I tilling off the solvent.

3. Theprocess of manufacturing varnish, which comprises the step of dissolving copal by heating the latter under pressure but not materially in excess of 250 pounds to the square inch, in the-presence of a relatively small quantity of mineral oil distillation.

t. The process of manufacturing varnish,

which comprises the step of dissolving copal by heating the latter under pressure but not materially in excess of 250 pounds to the square inch, in the presence of'a relatively small quantity of mineral oil distillation and simultaneously distilling 011' the solvent.

5. The process of manufacturing varnish,

by heating by heating the latter under pressure but not materially in excess of 250 pounds to the-- square inch, in the presence ofia quantity of a volatile solventlessthan required in the finished product and simultaneously dist-illing off the solvent and thereafter adding the requisite quantity of solvent.

6.. The process of manufacturing'varnish, which comprises the step of dissolving copal the latter under pressure ut not materially in excess of 250 pounds to the square inch, in the presence of a quantity of a volatile solvent less than required distilling off the solvent and thereafter at a in the finished product and simultaneously lower temperature adding} the 'requisite quantity of solvent.

7. The process ofmanufacturing varnish, which comprises the step of dissolving copal by heating the latter under pressure but not materially in excess of 250 pounds. -to the square inch, in the presence of a quantity of a volatile solvent less than required in the finished productand simultaneously distilling ofl' the solvent and thereafter thinning and filtering.

8. The process of manufacturing varnish,

which consists in dissolving copal by heat-v ing the latter under pressure but" not materially in excess of 250 pounds to thesquare inch, in the'presence of a relatively "small quantity of mineral oil distillation, simult'aneously distilling off the solvent and there-- after at a lower temperature adding the requisite quantity of turpentine for the finished product. a

In testimony where/oil have signed-my name to this specificatiom in the presence of two subscribing witnesses.

' EDWARD HALFORD STRANGE.

Witnesses:

Jon-N ROWLAND WHINCOP,' H. D. JAMESON. 

